Calcitonin induces connective tissue growth factor through ERK1/2 signaling in renal tubular cells.

Calcitonin (CT), a polypeptide hormone, plays important roles in a variety of physiological processes. CT has been used clinically to treat osteoporosis and humoral hypercalcemia of malignancy. In order to clarify the pharmacological effects of CT in the kidney, we identified potential downstream genes induced by CT in the renal cells. Using a cDNA subtraction hybridization method, we identified connective tissue growth factor (CTGF) as a CT-induced gene in the porcine renal cell line, LLC-PK1. Furthermore, we found that CT-mediated induction of the gene was not inhibited by cycloheximide, which suggests that CTGF gene was not induced by an increased synthesis of regulating proteins. Therefore, CTGF is an immediate early gene. We further demonstrated that the regulation of CTGF gene expression by CT involved the ERK1/2 pathway, because PD98059, a MEK1 inhibitor, partially inhibited the mRNA expression of CTGF induced by CT. CT-induced CTGF protein expression was also observed in vivo. Our present findings suggest that CT induces the transcription of CTGF through ERK1/2 phosphorylation. We also identified twelve other genes induced by CT that, like CTGF, were related to wound healing. These results suggest that CT may have an effect on renal differentiation and wound healing in the kidney.

Ultrastructural demonstration of hepatitis B virus production in a mouse model produced by hydrodynamic transfection.

A mouse model of hepatitis B virus (HBV) infection produced by hydrodynamic injection of HBV DNA has been recently established. However, the ultrastructural demonstration of HBV particles in this mouse model has not as yet been reported. In our study, plasmid DNA containing wild-type HBV DNA was rapidly injected into 8-week-old female SCID mice via the tail vein. Serum levels of HBsAg were measured by ELISA kit. Intrahepatic HBV protein expression was detected by immunohistochemistry of HBcAg. Ultrastructural study of the serum samples was performed by transmission electron microscopy and immunogold electron microscopy. Serum HBsAg and intrahepatic HBcAg were detected in HBV DNA-injected mice for at least 14 days. Spherical and filamentous particles 22 nm in diameter and double-shelled Dane-like particles 42 nm in diameter were detected in the sera of mice. The ultrastructural features of these particles were identical to HBV particles observed in serum from chronic hepatitis B patients. These particles were confirmed to be HBV particles by immunogold electron microscopy. We conclude that our present HBV mouse model using hydrodynamic transfection of HBV DNA is appropriate for production of HBV virions including Dane particles. This mouse model may be useful for screening in vivo the efficacy of antiviral drugs.

Hepatic arterial infusion of 5-fluorouracil in combination with subcutaneous interferon-alpha for advanced hepatocellular carcinoma.

BACKGROUND/AIMS: Transcatheter arterial chemoinfusion (TACI) is the main therapeutic modality for advanced hepatocellular carcinoma (HCC) with portal thrombus. However, TACI is not sufficient to improve prognosis. In this study, we evaluated the response to hepatic arterial infusion of 5-fluorouracil (5-FU) in combination with subcutaneous interferon (IFN)-alpha in patients with advanced HCC. METHODOLOGY: Ten patients (men, 8; women, 2; mean age, 55-77) with advanced HCC were enrolled in this study. Hepatic arterial infusion of 5-FU (500 mg/24 hrs) was performed for 5 days on the first and second week. IFN-alpha (5 x 10(6) International Units) was subcutaneously administered three times a week for 4 weeks (1 therapeutic course). Response to therapy was evaluated by abdominal computed tomography at the end of two courses of therapy. RESULTS: Seven patients received more than two courses of therapy. One patient (14%) showed complete response (CR). Four patients had stable disease (SD) (57%) and the remaining 2 patients had progressive disease (PD) (29%). Tumor markers decreased in all patients except 1 with PD. The 6-month survival rate was 40%. Therapy was discontinued in 3 patients due to severe adverse effects; all of these patients were over 70 years old, and had moderate liver dysfunction (Child-Pugh score of Grade B) before initiation of therapy. CONCLUSIONS: The goal of the therapy with hepatic arterial infusion of 5-FU in combination with subcutaneous IFN-alpha was attained in only 14% among our advanced HCC patients. The tumor completely disappeared in 1 patient, suggesting that this therapeutic modality may be of potential benefit in advanced HCC patients. However, this therapy should be performed with caution in patients with poor hepatic function (grade B or C of Child-Pugh score) and in those more than 70 years old.

Unidentified virus-like particles are detected in plasmas with elevated ALT levels: are they significant of etiological agent(s) of non-B, non-C hepatitis?

GB virus C (GBV-C) and hepatitis G virus (HGV) have been proposed as new viruses etiologically implicated in non-B, non-C hepatitis, but the morphology of these particular virus particles is still unknown, and most cases of non-A to E hepatitis do not relate to their infections. We tried to visualize virus-like particles (VLPs) in plasma samples from hepatitis B surface antigen- and antibody to hepatitis C virus (HCV)-negative blood donors with elevated alanine aminotransferase (ALT), and examined the association of the virus-like particles and the genomes of parenterally transmissible GBV-C/HGV. Twenty-three plasma samples, 13 with elevated ALT levels and 10 with normal ALT values, from blood donors without infections of hepatitis B virus (HBV) and HCV, were subjected to a 20%-60% sucrose density gradient centrifugation, and virus-like particles were observed by electron microscopy. GBV-C/HGV RNAs in the plasmas were tested. Virus-like particles were found in the fractions with densities of 1.15-1.16 g/ml from 12 of 13 (92.3%) plasmas with elevated ALT levels and 1 of 10 (10%) normal controls. The ultrastructural morphology of visualized VLPs was pleomorphic in size and appearance; the majority of the VLPs were 50- to 80-nm spherical particles with a 35- to 45-nm inner core and 9- to 12-nm-long surface spike-like projections. Rodlike VLPs 50-70 nm in diameter with a length of 110-160 nm were also observed in the same samples. The incidence of detection of the circulating VLPs was significantly (P < 0.001) related to elevated ALT levels, but GBV-C/HGV RNAs were detected in none of the plasmas containing the virus-like particles. Spherical VLPs are detected in HBV- and HCV-negative plasmas significantly correlated with the elevation of ALT, suggesting that they are implicated in non-B, non-C hepatitis.

Restriction of dietary calories, fat and iron improves non-alcoholic fatty liver disease.

BACKGROUND: The pathogenesis of non-alcoholic steatohepatitis (NASH) is unclear. Recent studies suggested that oxidative stress plays an important role in the mechanism of NASH. Excessive accumulation of iron in the liver causes oxidative stress. The aim of the present study was to evaluate the grade of hepatic iron accumulation and the therapeutic response to restriction of calories, fat and iron in patients with non-alcoholic fatty liver disease (NAFLD). METHODS: Twenty-seven NAFLD patients were enrolled. The patients were categorized into two groups: 17 patients with NASH and 10 with simple steatosis. Twelve NAFLD patients (NASH, n = 9; simple steatosis, n = 3) were given a dietary prescription including restriction of energy, fat and iron. RESULTS: Positive iron staining was observed in 71% and 50% of patients with NASH and simple steatosis, respectively. The average energy intake, fat energy fraction and iron intake decreased significantly 6 months after the beginning of the diet in all patients. In addition, the levels of serum transaminase and ferritin were significantly decreased. CONCLUSION: Dietary restriction of calories, fat and iron improved NAFLD. Reduced serum ferritin levels appear to reduce oxidative stress in the liver.

Increased lipid peroxidation in patients with non-alcoholic fatty liver disease and chronic hepatitis C as measured by the plasma level of 8-isoprostane.

BACKGROUND: Oxidative stress plays an important role in the pathogenesis of chronic liver diseases. The plasma level of 8-isoprostane, a product of lipid peroxidation, is a marker of oxidative stress in vivo. The aim of the present study was to clarify whether the degree of lipid peroxidation, as measured by the plasma level of 8-isoprostane, influences the progression of chronic liver diseases and hepatocarcinogenesis. METHODS: Plasma 8-isoprostane levels were investigated in 14 patients with non-alcoholic fatty liver disease (NAFLD), 75 with chronic hepatitis C (CH-C), 14 with cured CH-C, 14 with HCV-positive hepatocellular carcinoma (HCC-C) and 38 healthy volunteers. 8-Isoprostane was measured by enzyme immunoassay after affinity column purification. RESULTS: Plasma 8-isoprostane was significantly elevated in NAFLD (11.9 [3.8-56.8] pg/mL), CH-C (10.1 [4.2-134.5] pg/mL) as compared to controls (6.3 [3.6-11.1] pg/mL). Plasma 8-isoprostane values were positively correlated with body mass index in NAFLD (P < 0.05) and with total cholesterol in cured CH-C (P < 0.01). 8-Isoprostane levels were not significantly related to sex, age, biochemical data or iron metabolism markers in all liver diseases. In addition, after the administration of peg-interferon, the values of 8-isoprostane improved in almost all patients, reaching values of healthy subjects. CONCLUSIONS: 8-Isoprostane values are elevated in patients with NAFLD and CH-C as compared to healthy controls. Oxidative stress caused by increased lipid peroxidation is involved in the pathogenesis of NAFLD and CH-C.

siRNA-resistance in treated HCV replicon cells is correlated with the development of specific HCV mutations.

RNA interference (RNAi) has been extremely effective against hepatitis C viral (HCV) gene expression in short-term cell culture. Our aim was to determine whether long-term RNAi might result in HCV-resistant mutants. Huh7 HCV subgenomic replicon cells were transfected with short interfering RNAs (siRNAs). HCV-RNA was quantified by real-time RT-PCR, and HCV NS5A levels were assayed by Western blots using specific antibody. Treatment with HCV-siRNA resulted in a 50% inhibition of HCV-RNA levels compared with pretreatment levels after 4 weeks (P < 0.05). HCV-RNA returned to 85% of pretreatment levels after cessation of HCV-siRNA treatment. Sequencing of the HCV-siRNA target and upstream region was performed on 10 colonies from subcloning using PCR products, each before, during and after siRNA treatment. All colonies except one from HCV-siRNA-treated cells during and after treatment had mutations. There were no mutations in the HCV-siRNA target region following control HBV-siRNA treatment. Subcloned replicon cells containing the point mutations in the target region were found to be resistant to HCV-siRNA inhibitory effects. In conclusion, even after 4 weeks of treatment of replicon cells with HCV-siRNA, HCV-RNA and HCV-NS5A protein expression could not be completely eliminated. HCV replicons isolated during or after treatment were associated with mutations in the siRNA target region, while controls were not.

Morphological identification of hepatitis C virus E1 and E2 envelope glycoproteins on the virion surface using immunogold electron microscopy.

It is known that hepatitis C virus (HCV) particles are spherical, 55-65 nm particles with fine surface projections of about 6 nm in length and with a 30-35 nm inner core. We have reported that free HCV particles labeled with gold particles specific to the HCV E1 glycoprotein are located in 1.14-1.16 g/ml fractions from plasma samples with high HCV RNA titers after sucrose density gradient centrifugation. However, the morphology of the HCV E2 glycoprotein on the virion has not yet been elucidated. To visualize HCV E2 localization on the virion, we used the same plasma samples where HCV particles were clearly shown. An indirect immunogold electron microscopic study was carried out using monoclonal and polyclonal anti-HCV E2 antibodies. HCV-like particles specifically reacted with the anti-HCV E2 antibodies. Moreover, to evaluate the localization of the HCV E1 and E2 glycoproteins on the virion surface, an immunogold electron microscopic study using double labeling with anti-HCV E1 antibodies and anti-HCV E2 antibodies was also performed. These particles also specifically reacted with both anti-E1 and E2 antibodies. This is the first report showing the presence of both HCV E1 and E2 glycoproteins on HCV virion surface in human plasma samples.

The ultrastructural morphology of native hepatitis B virus.

Cell lines (2.2.15 cells) capable of supporting the replication of hepatitis B virus (HBV) DNA and intact viral particles have been established by HBV DNA transfection into HepG2 cells. The purpose of this study was to determine the ultrastructural morphology of native HBV particles without purification in the culture supernatants and in sera from patients. Electron microscopy (EM) and immunogold EM of the samples were carried out using polyclonal and monoclonal anti-hepatitis B surface antigen antibodies. HBV particles in the purified samples from the culture supernatants by density-gradient centrifugation were examined to compare the morphology with that of unpurified samples. EM and immunogold EM studies demonstrated the presence of Dane particles (41.8 nm in diameter), cobra-shaped (head diameter, 42.4 nm), and horn-shaped (head diameter, 43.5 nm) particles in the culture supernatants and in the sera from two patients. The tail of the cobra-like particles had a diameter of 21.0 nm and a length of 214 nm. The hornlike particles had a long branch 20.1 nm in diameter with a length of 189 nm, and a short branch 21.4 nm in diameter with a length of 112 nm. The ratio of Dane particles and cobra- and horn-shaped particles in the supernatants was 5 : 4 : 1. After ultracentrifugation, the cobra- and horn-shaped particles completely disappeared; there were only Dane particles together with spheres of 22 nm and filaments. In conclusion, this study showed for the first time that the native replicative form of HBV is cobra- and horn-shaped.

Lactoferrin inhibits lipid peroxidation in patients with chronic hepatitis C.

Lactoferrin is a milk protein with inhibitory effect on lipid peroxidation induced by oxidative stress. Oxidative stress plays an important role in the pathogenesis of chronic hepatitis C (CHC). The aim of this study was to evaluate the effect of bovine lactoferrin (bLF) monotherapy on lipid peroxidation, hepatic inflammation and iron metabolism in patients with CHC. Ninety Japanese patients with CHC were randomly assigned to two groups: bLF group (n=47) treated with bLF at a dose of 3.6g/day and a control group (n=43) that remained untreated. Plasma 8-isoprostane levels and clinical laboratory data including iron metabolism parameters were measured. Plasma 8-isoprostatne level was significantly decreased from 8.6+/-3.7 to 6.9+/-2.1pg/ml in the bLF group (P<0.05). Plasma levels of 8-isoprostane did not significantly change in the control group. The decline in plasma 8-isoprostane levels was positively correlated with improvement in the level of ALT in the bLF group. No significant change in serum HCV RNA levels or iron metabolism markers was found after bLF treatment. Therapy with bLF was associated with improvement in lipid peroxidation and ALT levels in CHC. Administration of bLF is a promising therapeutic approach for suppressing oxidative stress in non-responders to antiviral therapy.

Morphology of hepatitis C and hepatitis B virus particles as detected by immunogold electron microscopy.

We performed indirect immunogold electron microscopy (EM) for immunological identification and characterization of hepatitis C virus (HCV). To clarify the morphology of HCV, an indirect immunogold EM of two plasma samples from patients with high HCV RNA titers was carried out using antibodies specific for the putative HCV envelope protein (E) 1. Spherical virus particles 55-65 nm in diameter with delicate spike projections were detected in the 1.14-1.16 g/ml fractions after sucrose density gradient centrifugation. Polyclonal and monoclonal antibodies to the putative HCV E1 specifically recognized these particles. In addition, immunogold EM of the samples was also performed to uncover the morphology of HCV core particles. Spherical particles 33-40 nm in diameter (average, 37 nm) were detected in the 1.22- to 1.25-g/ml fractions by conventional EM after sucrose density gradient centrifugation. Immunogold EM using rabbit polyclonal antibody (RR8) specific for the putative HCV core protein and colloidal gold-labeled goat antirabbit IgG showed binding of the gold particles with RR8. Some of the HCV core particles showed icosahedric morphology. Optical rotation technique showed that the HCV core particles exhibit sixfold symmetry and that the length of the regular hexagon side is approximately 20 nm, suggesting that they have an icosahedric structure. Further, the detection limit of the indirect immunogold EM was evaluated in 11 plasma samples from chronic hepatitis B patients with different degrees of hepatitis B virus (HBV) DNA titers using antihepatitis B surface antigen antibody. The study showed that the detection limit of virus using this method is 10(7) virions/ml.

Novel delivery methods for treatment of viral hepatitis: an update.

Viral hepatitis represents the most common cause of chronic liver disease worldwide. Currently approved therapies for chronic hepatitis B include IFN, an immune modulator, and nucleoside analogues lamivudine and adefovir. For chronic hepatitis C, a combination of pegylated IFN-alpha and ribavirin represents the standard treatment. However, currently available treatments for both these viruses are effective only in a limited number of patients, are costly, prolonged, associated with significant side effects and require a substantial commitment from the patients and healthcare providers. A number of novel antiviral treatments, together with strategies to enhance the response to current therapies, are being explored at present. For all new therapies, as well as for improving existing treatments, selective delivery of medications into liver cells would be desirable to enhance antiviral activity and avoid systemic side effects. New achievements in the field of drug and gene delivery against chronic hepatitis to the liver are reviewed here.

A novel immunocompetent rat model of HCV infection and hepatitis.

BACKGROUND & AIMS: Hepatitis C virus (HCV) infects millions of people worldwide. Therapy is limited, and treatment does not produce a sustained response in the majority of patients. Development of new agents has been hampered by the lack of a convenient animal model. The aim of this study was to determine whether an immunocompetent rat, tolerized and transplanted with a human hepatoma cell line (Huh 7 cells), could be used to sustain an HCV infection. METHODS: Fetal rats were tolerized in utero with 10(5) Huh 7 cells. One day after birth, rats were transplanted with 5 x 10(6) Huh 7 cells and, a week later, inoculated with HCV, genotype 1. RESULTS: In tolerized, transplanted, and HCV-infected rats, Huh 7 cells were found in the liver, and HCV viral replication was detected by the presence of negative strand HCV RNA. HCV levels in serum were measured at 11,000 copies/mL at week 4, peaked at 22,500 copies/mL by week 12. In tolerized, transplanted, inoculated rats, but not controls, serum alanine aminotransferase (ALT) values increased to 60 IU/L by week 4 and reached a peak of approximately 120 IU/L by week 13. Histology showed foci of mononuclear infiltrates in portal and central regions. CONCLUSIONS: HCV-inoculated immunocompetent rats tolerized and transplanted with Huh 7 cells support HCV gene expression, viral replication, and develop biochemical and histologic evidence of hepatitis.

Inhibition of HBV replication by siRNA in a stable HBV-producing cell line.

Potent inhibition of endogenous gene expression by RNA interference has been achieved by using sequence-specific posttranscriptional gene silencing through the action of small interfering RNA molecules (siRNA). In these reports, the natural function of genes could be deduced through the ensuing loss of function. Based on the extraordinary effectiveness in silencing endogenous genes, we wondered whether siRNA could be applied against viral replication in a hepatitis B virus (HBV) model using HBV-specific siRNA. To test this idea, HepG2 2.2.15, a human hepatoblastoma cell line that constitutively produces infectious HBV particles, was transfected with HBV-specific siRNAs and controls. HBV surface antigen (HBsAg) secretion into culture media was inhibited by 78%, 67%, and 42% with siRNA against the polyadenylation (PA), precore (PreC), and surface (S) regions, respectively, compared with controls as detected by enzyme-linked immunosorbent assay. After exposure to HBVPA siRNA, Northern blot analysis showed that HBV pregenomic RNA levels were decreased by 72%, and levels of HBV RNA containing the polyadenylation signal sequence were suppressed by 86%, as detected by RNase protection assay. Levels of HBV core-associated DNA, a replication intermediate, also decreased by 71%. Immunocytochemistry revealed that 30% to 40% of the cells transfected with HBVPA siRNA were completely negative for detectable HBsAg levels. Controls consisting of treatment with HBV-specific siRNA alone, lipofection reagent alone, or random double-stranded RNA (dsRNA) lipofection complex failed to decrease HBV surface antigen, HBV messenger RNA (mRNA), or core-associated HBV-DNA levels. In conclusion, siRNA inhibits hepatitis B viral replication in a cell culture system. Future studies are needed to explore the specific delivery of siRNA to liver cells in vivo and the applicability of this approach.